WO2011021860A9 - Method of fabricating array substrate for liquid crystal display - Google Patents

Method of fabricating array substrate for liquid crystal display Download PDF

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Publication number
WO2011021860A9
WO2011021860A9 PCT/KR2010/005484 KR2010005484W WO2011021860A9 WO 2011021860 A9 WO2011021860 A9 WO 2011021860A9 KR 2010005484 W KR2010005484 W KR 2010005484W WO 2011021860 A9 WO2011021860 A9 WO 2011021860A9
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Prior art keywords
layer
etchant composition
based metal
metal layer
copper
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PCT/KR2010/005484
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French (fr)
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WO2011021860A2 (en
WO2011021860A3 (en
Inventor
Hyun-Kyu Lee
Woo-Ram Lee
Kyung-Sub Jung
Yong-Suk Choi
Suk Lee
Young-Jin Yoon
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Dongwoo Fine-Chem Co., Ltd.
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Priority claimed from KR1020090077211A external-priority patent/KR101586865B1/en
Priority claimed from KR1020090077546A external-priority patent/KR101586500B1/en
Application filed by Dongwoo Fine-Chem Co., Ltd. filed Critical Dongwoo Fine-Chem Co., Ltd.
Priority to CN201080037314.9A priority Critical patent/CN102576170B/en
Publication of WO2011021860A2 publication Critical patent/WO2011021860A2/en
Publication of WO2011021860A3 publication Critical patent/WO2011021860A3/en
Publication of WO2011021860A9 publication Critical patent/WO2011021860A9/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/02—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components specially adapted for rectifying, oscillating, amplifying or switching and having potential barriers; including integrated passive circuit elements having potential barriers
    • H01L27/12—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components specially adapted for rectifying, oscillating, amplifying or switching and having potential barriers; including integrated passive circuit elements having potential barriers the substrate being other than a semiconductor body, e.g. an insulating body
    • H01L27/1214—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components specially adapted for rectifying, oscillating, amplifying or switching and having potential barriers; including integrated passive circuit elements having potential barriers the substrate being other than a semiconductor body, e.g. an insulating body comprising a plurality of TFTs formed on a non-semiconducting substrate, e.g. driving circuits for AMLCDs
    • H01L27/124—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components specially adapted for rectifying, oscillating, amplifying or switching and having potential barriers; including integrated passive circuit elements having potential barriers the substrate being other than a semiconductor body, e.g. an insulating body comprising a plurality of TFTs formed on a non-semiconducting substrate, e.g. driving circuits for AMLCDs with a particular composition, shape or layout of the wiring layers specially adapted to the circuit arrangement, e.g. scanning lines in LCD pixel circuits

Definitions

  • the present invention relates to a method of fabricating an array substrate for a liquid crystal display, an etchant composition for a copper-based metal layer, and a method of etching a copper-based metal layer using the etchant composition.
  • forming metal wiring on a substrate of a semiconductor device includes forming a metal layer using sputtering, applying a photoresist, performing light exposure and development so that the photoresist is formed on a selective region, and performing etching, and a cleaning process is conducted before or after each individual process.
  • the etching process is carried out such that the metal layer is formed on a selective region using the photoresist as a mask, and the etching process typically includes dry etching using plasma or wet etching using an etchant composition.
  • chromium Cr, resistivity: 12.7 ⁇ 10 -8 ⁇ m
  • molybdenum Mo, resistivity: 5 ⁇ 10 -8 ⁇ m
  • aluminum Al, resistivity: 2.65 ⁇ 10 -8 ⁇ m
  • alloys thereof have high resistance, and are therefore difficult to use for the gate and data wiring of large-sized TFT-LCDs.
  • a low-resistance metal layer comprising a copper (Cu)-based metal layer such as a Cu layer or a Cu-Mo layer, and a related etchant composition are receiving attention.
  • Cu copper
  • etchant compositions for Cu-based metal layers known to date do not satisfy the performance demanded by users, research and development into increasing such performance is ongoing.
  • the present invention is intended to provide an etchant composition for a Cu-based metal layer, in which a taper profile having superior etching uniformity and linearity is formed and there is no metal layer residue.
  • the present invention is intended to provide an etchant composition for a Cu-based metal layer, which may etch all of a gate electrode, gate wiring, source/drain electrodes and data wiring of a liquid crystal display made of Cu-based metal.
  • the present invention is intended to provide a method of etching a Cu-based metal layer and a method of fabricating an array substrate for a liquid crystal display, using the above etchant composition.
  • An aspect of the present invention provides an etchant composition for a Cu-based metal layer, comprising, based on the total weight of the composition, A) 5.0 ⁇ 25 wt% of hydrogen peroxide (H 2 O 2 ), B) 0.01 ⁇ 1.0 wt% of a fluorine (F)-containing compound, C) 0.1 ⁇ 5.0 wt% of an azole compound, D) 0.1 ⁇ 10.0 wt% of one or more compounds selected from among phosphonic acid derivatives and salts thereof, and E) a remainder of water.
  • Another aspect of the present invention provides a method of etching a Cu-based metal layer, comprising forming a Cu-based metal layer on a substrate, selectively forming a photosensitive material layer on the Cu-based metal layer, and etching the Cu-based metal layer using the etchant composition according to the present invention.
  • a further aspect of the present invention provides a method of fabricating an array substrate for a liquid crystal display, comprising a) forming gate wiring on a substrate, b) forming a gate insulating layer on the substrate including the gate wiring, c) forming a semiconductor layer on the gate insulating layer, d) forming source/drain electrodes on the semiconductor layer, and e) forming a pixel electrode connected to the drain electrode, wherein a) comprises forming a Cu-based metal layer on the substrate, and etching the Cu-based metal layer using the etchant composition according to the present invention, thus forming the gate wiring, and d) comprises forming a Cu-based metal layer on the semiconductor layer and etching the Cu-based metal layer using the etchant composition according to the present invention, thus forming the source/drain electrodes.
  • Still another aspect of the present invention provides an array substrate for a liquid crystal display, comprising one or more selected from among gate wiring and source/drain electrodes, each of which is etched using the etchant composition according to the present invention.
  • a taper profile having superior etching uniformity and linearity can be formed, and also, etching residue is not generated, thus preventing electrical shorts, poor wiring or low luminance from occurring.
  • all of a gate electrode, gate wiring, source/drain electrodes and data wiring of a liquid crystal display made of Cu-based metal may be etched by the etchant composition, thus simplifying the etching process and maximizing the process yield.
  • the etchant composition according to the present invention can be very efficiently used to fabricate an array substrate for a liquid crystal display, which has circuitry in order that a large screen and high luminance can be realized.
  • FIGS. 1 and 2 are scanning electron microscope (SEM) images respectively showing the cross-section and the whole etching profile of a Cu/Mo-Ti double layer etched using an etchant composition (Example 1) according to the present invention;
  • FIGS. 3 and 4 are SEM images respectively showing the cross-section and the whole etching profile of a Cu/Mo-Ti double layer etched using an etchant composition (Example 7) according to the present invention.
  • FIGS. 5 and 6 are SEM images showing the surface around the Cu wiring of a Cu/Mo-Ti double layer etched using an etchant composition of Example 1 and an etchant composition of Example 7 according to the present invention, respectively.
  • the present invention is directed to an etchant composition for a Cu-based metal layer, which comprises, based on the total weight of the composition, A) 5.0 ⁇ 25 wt% of hydrogen peroxide (H 2 O 2 ), B) 0.01 ⁇ 1.0 wt% of a F-containing compound, C) 0.1 ⁇ 5.0 wt% of an azole compound, D) 0.1 ⁇ 10.0 wt% of one or more compounds selected from among phosphonic acid derivatives and salts thereof, and E) a remainder of water.
  • H 2 O 2 hydrogen peroxide
  • the Cu-based metal layer which contains Cu therein, may have a single layer structure or a multilayer structure including a double layer and the like, and examples thereof include a single layer of Cu or Cu alloy, and a multilayer such as a Cu-Mo layer, or a Cu-Mo alloy layer.
  • the Cu-Mo layer includes a Mo layer and a Cu layer formed on the Mo layer
  • the Cu-Mo alloy layer includes a Mo alloy layer and a Cu layer formed on the Mo alloy layer.
  • the Mo alloy layer can be composed of Mo and one or more selected from among titanium (Ti), tantalum (Ta), chromium (Cr), nickel (Ni), neodymium (Nd), and indium (In).
  • the A) hydrogen peroxide (H 2 O 2 ) is a main component for etching the Cu-based metal layer, and is used in an amount of 5.0 ⁇ 25 wt% based on the total weight of the composition. If the amount of the A) hydrogen peroxide is less than 5.0 wt%, the Cu-based metal may not be etched or the etching rate may become too slow. In contrast, if the amount thereof exceeds 25 wt%, the total etching rate may become fast, making it difficult to control the process.
  • the B) F-containing compound is a compound which dissociates in water to produce F ion.
  • the B) F-containing compound functions to remove the inevitably generated etching residue from the etchant which etches the Cu layer and the Mo layer simultaneously.
  • the B) F-containing compound is used in an amount of 0.01 ⁇ 1.0 wt% based on the total weight of the composition. If the amount of the B) F-containing compound is less than 0.01 wt%, etching residue may result. In contrast, if the amount thereof exceeds 1.0 wt%, the rate at which the glass substrate is etched may increase.
  • the B) F-containing compound may include any material used in the art without limitation so long as it dissociates in water to produce F ion or polyatomic F ions when in solution, and may include one or more selected from the group consisting of ammonium fluoride (NH 4 F), sodium fluoride (NaF), potassium fluoride (KF), ammonium bifluoride (NH 4 FHF), sodium bifluoride (NaFHF) and potassium bifluoride (KFHF).
  • NH 4 F ammonium fluoride
  • NaF sodium fluoride
  • KF potassium fluoride
  • NH 4 FHF ammonium bifluoride
  • NaFHF sodium bifluoride
  • KFHF potassium bifluoride
  • the C) azole compound functions to adjust the rate at which the Cu-based metal is etched and to reduce CD loss of the pattern so that the process margin is increased.
  • the C) azole compound is used in an amount of 0.1 ⁇ 5.0 wt% based on the total weight of the composition. If the amount of the C) azole compound is less than 0.1 wt%, the etching rate may increase and thus too much CD loss may result. In contrast, if the amount thereof exceeds 5.0 wt%, the Cu etching rate may decrease and the Mo or Mo alloy etching rate may increase, and thus the Mo or Mo alloy may be over-etched undesirably causing under-cut.
  • Examples of the C) azole compound include aminotetrazole, benzotriazole, tolytriazole, pyrazole, pyrrole, imidazole, 2-methylimidazole, 2-ethylimidazole, 2-propylimidazole, 2-aminoimidazole, 4-methylimidazole, 4-ethylimidazole, and 4-propylimidazole, which may be used alone or in mixtures of two or more.
  • the D) one or more compounds selected from among phosphonic acid derivates and salts thereof function to chelate Cu ions dissolved in the etchant when a Cu layer is etched, so as to suppress the activity of Cu ions to thereby inhibit the decomposition of hydrogen peroxide.
  • the D) one or more compounds selected from among phosphonic acid derivates and salts thereof are used in an amount of 0.1 ⁇ 10.0 wt% based on the total weight of the composition.
  • the amount of the D) one or more compounds selected from among phosphonic acid derivates and salts thereof is less than 0.1 wt%, etching uniformity may be lowered and decomposition of hydrogen peroxide may be accelerated. In contrast, if the amount thereof exceeds 10.0 wt%, the etching rate may becomes too fast.
  • a typical example of the phosphonic acid derivative may include 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP), and a typical example of the salt of phosphonic acid derivative may include a sodium or potassium salt of HEDP.
  • HEDP 1-hydroxyethylidene-1,1-diphosphonic acid
  • the E) water is not particularly limited but may include deionized water. Particularly useful is deionized water having a resistivity (which is the degree of ions being removed from water) of 18 M ⁇ /cm or more.
  • the etchant composition according to the present invention may further comprise F) one or more compounds selected from among acetates and peracetates. These compounds play a role in increasing the uniformity of etching.
  • one or more compounds selected from among acetates and peracetates may be used in an amount of 0.05 ⁇ 5.0 wt% based on the total weight of the composition. If the amount of one or more compounds selected from among acetates and peracetates is less than 0.05 wt%, etching uniformity may be lowered. In contrast, if the amount thereof exceeds 5.0 wt%, the etching rate may become too slow.
  • typical examples of the acetates may include ammonium acetate, sodium acetate, and potassium acetate
  • typical examples of the peracetates may include ammonium peracetate, sodium peracetate, and potassium peracetate.
  • the etchant composition according to the present invention may further comprise a surfactant.
  • the surfactant functions to lower surface tension so as to increase etching uniformity.
  • the surfactant is not particularly limited so long as it is resistant to the etchant composition according to the present invention and has compatibility, but may include one or more selected from the group consisting of an anionic surfactant, a cationic surfactant, an amphoteric surfactant, a non-ionic surfactant, and a polyhydric alcohol surfactant.
  • the etchant composition according to the present invention may further comprise a typical additive, in addition to the above components.
  • a typical additive may include a sequestering agent, an anticorrosive agent and so on.
  • the etchant composition comprising the A) hydrogen peroxide (H 2 O 2 ), the B) F-containing compound, the C) azole compound, the D) one or more compounds selected from among phosphonic acid derivates and salts thereof, and the E) water may be prepared using typically known methods, and preferably is of a purity suitable for semiconductor processes.
  • the etchant composition according to the present invention may etch all of a gate electrode, gate wiring, source/drain electrodes and data wiring of a liquid crystal display made of Cu-based metal.
  • the present invention is directed to a method of etching a Cu-based metal layer, comprising I) forming a Cu-based metal layer on a substrate, II) selectively forming a photosensitive material layer on the Cu-based metal layer, and III) etching the Cu-based metal layer using the etchant composition according to the present invention.
  • the photosensitive material may be a typical photoresist, and the photosensitive material layer may be selectively formed using typical exposure and development.
  • the present invention is directed d to a method of fabricating an array substrate for a liquid crystal display, comprising a) forming gate wiring on a substrate, b) forming a gate insulating layer on the substrate including the gate wiring, c) forming a semiconductor layer on the gate insulating layer, d) forming source/drain electrodes on the semiconductor layer, and e) forming a pixel electrode connected to the drain electrode, wherein a) may comprise forming a Cu-based metal layer on the substrate and etching the Cu-based metal layer using the etchant composition according to the present invention, thus forming the gate wiring, and d) may comprise forming a Cu-based metal layer on the semiconductor layer and etching the Cu-based metal layer using the etchant composition according to the present invention, thus forming the source/drain electrodes.
  • the array substrate for a liquid crystal display may be a TFT array substrate.
  • Etchant compositions of Examples 1 to 12 were prepared using the components shown in Table 1 below.
  • Etching of Cu-based metal layers was performed using the etchant compositions of Examples 1 to 12.
  • the temperature of the etchant composition was set to about 30°C, but may appropriately vary depending on the other process conditions and factors.
  • the etching time may vary depending on the etching temperature, it was generally set to about 30 ⁇ 180 sec.
  • the cross-section profile of the etched Cu-based metal layer in the etching process was observed using SEM (S-4700, available from Hitachi). The results are shown in Table 2 below.
  • evaluating the etching rates of Examples 1 to 12 shows these etching rates to be appropriate. From FIGS. 1 and 2 showing the Cu/Mo-Ti etched using the composition of Example 1 and from FIGS. 3 and 4 showing the Cu/Mo-Ti etched using the composition of Example 7, it can be seen that the Cu-based metal layer etched using the etchant composition of Example 1 or 7 represents a good etching profile. Also, from FIG. 5 showing the Cu/Mo-Ti etched using the composition of Example 1 and from FIG. 6 showing the Cu/Mo-Ti etched using the composition of Example 7, it can be seen that when the Cu-based metal layer is etched using the etchant composition of Example 1 or 7, there is no etching residue.
  • the etchant composition according to the present invention is advantageous because of the superior taper profile of the Cu-based metal layer, pattern linearity, and appropriate etching rate, and in particular there is no etching residue left behind after etching.
  • the etchant composition of Example 9 further comprising the acetate has no difference in the side etch for any number of processing substrate s .
  • the acetate functions to prevent taper rounding of the upper Cu layer which may occur in proportion to the increase in the number of processing substrate s when the etchant composition such as Example 3 is used.

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  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
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Abstract

Disclosed is a method of fabricating an array substrate for a liquid crystal display, including forming a copper-based metal layer on a substrate and etching the copper-based metal layer using an etchant composition thus forming gate wiring, and forming a copper-based metal layer on a semiconductor layer and etching the copper-based metal layer using the etchant composition thus forming source/drain electrodes, the etchant composition including based on the total weight of the composition, A) 5.0 ~ 25 wt% of hydrogen peroxide (H2O2), B) 0.01 ~ 1.0 wt% of a fluorine-containing compound, C) 0.1 ~ 5.0 wt% of an azole compound, D) 0.1 ~ 10.0 wt% of one or more compounds selected from among phosphonic acid derivatives and salts thereof, and E) a remainder of water.

Description

METHOD OF FABRICATING ARRAY SUBSTRATE FOR LIQUID CRYSTAL DISPLAY
The present invention relates to a method of fabricating an array substrate for a liquid crystal display, an etchant composition for a copper-based metal layer, and a method of etching a copper-based metal layer using the etchant composition.
Typically, forming metal wiring on a substrate of a semiconductor device includes forming a metal layer using sputtering, applying a photoresist, performing light exposure and development so that the photoresist is formed on a selective region, and performing etching, and a cleaning process is conducted before or after each individual process. The etching process is carried out such that the metal layer is formed on a selective region using the photoresist as a mask, and the etching process typically includes dry etching using plasma or wet etching using an etchant composition.
In such semiconductor devices, resistance of the metal wiring is recently being deemed important. This is because resistance is a main factor when it comes to inducing RC signal delay. In the case of thin film transistor-liquid crystal displays (TFT-LCDs), solving RC signal delay problems is the key to increasing the size of a panel and achieving high resolution. Thus, in order to accomplish the reduced RC signal delay that is essentially required to increase the size of a TFT-LCD, it is necessary to develop materials having low resistance.
Conventionally, chromium (Cr, resistivity: 12.7 ×10-8 Ωm), molybdenum (Mo, resistivity: 5 ×10-8 Ωm), aluminum (Al, resistivity: 2.65 ×10-8 Ωm) and alloys thereof have high resistance, and are therefore difficult to use for the gate and data wiring of large-sized TFT-LCDs. Hence, a low-resistance metal layer comprising a copper (Cu)-based metal layer such as a Cu layer or a Cu-Mo layer, and a related etchant composition are receiving attention. However, because etchant compositions for Cu-based metal layers known to date do not satisfy the performance demanded by users, research and development into increasing such performance is ongoing.
Accordingly, the present invention is intended to provide an etchant composition for a Cu-based metal layer, in which a taper profile having superior etching uniformity and linearity is formed and there is no metal layer residue.
Also the present invention is intended to provide an etchant composition for a Cu-based metal layer, which may etch all of a gate electrode, gate wiring, source/drain electrodes and data wiring of a liquid crystal display made of Cu-based metal.
Also the present invention is intended to provide a method of etching a Cu-based metal layer and a method of fabricating an array substrate for a liquid crystal display, using the above etchant composition.
An aspect of the present invention provides an etchant composition for a Cu-based metal layer, comprising, based on the total weight of the composition, A) 5.0 ~ 25 wt% of hydrogen peroxide (H2O2), B) 0.01 ~ 1.0 wt% of a fluorine (F)-containing compound, C) 0.1 ~ 5.0 wt% of an azole compound, D) 0.1 ~ 10.0 wt% of one or more compounds selected from among phosphonic acid derivatives and salts thereof, and E) a remainder of water.
Another aspect of the present invention provides a method of etching a Cu-based metal layer, comprising forming a Cu-based metal layer on a substrate, selectively forming a photosensitive material layer on the Cu-based metal layer, and etching the Cu-based metal layer using the etchant composition according to the present invention.
A further aspect of the present invention provides a method of fabricating an array substrate for a liquid crystal display, comprising a) forming gate wiring on a substrate, b) forming a gate insulating layer on the substrate including the gate wiring, c) forming a semiconductor layer on the gate insulating layer, d) forming source/drain electrodes on the semiconductor layer, and e) forming a pixel electrode connected to the drain electrode, wherein a) comprises forming a Cu-based metal layer on the substrate, and etching the Cu-based metal layer using the etchant composition according to the present invention, thus forming the gate wiring, and d) comprises forming a Cu-based metal layer on the semiconductor layer and etching the Cu-based metal layer using the etchant composition according to the present invention, thus forming the source/drain electrodes.
Still another aspect of the present invention provides an array substrate for a liquid crystal display, comprising one or more selected from among gate wiring and source/drain electrodes, each of which is etched using the etchant composition according to the present invention.
When a Cu-based metal layer is etched using an etchant composition according to the present invention, a taper profile having superior etching uniformity and linearity can be formed, and also, etching residue is not generated, thus preventing electrical shorts, poor wiring or low luminance from occurring.
Also, when an array substrate for a liquid crystal display is fabricated using the etchant composition according to the present invention, all of a gate electrode, gate wiring, source/drain electrodes and data wiring of a liquid crystal display made of Cu-based metal may be etched by the etchant composition, thus simplifying the etching process and maximizing the process yield.
Therefore, the etchant composition according to the present invention can be very efficiently used to fabricate an array substrate for a liquid crystal display, which has circuitry in order that a large screen and high luminance can be realized.
FIGS. 1 and 2 are scanning electron microscope (SEM) images respectively showing the cross-section and the whole etching profile of a Cu/Mo-Ti double layer etched using an etchant composition (Example 1) according to the present invention;
FIGS. 3 and 4 are SEM images respectively showing the cross-section and the whole etching profile of a Cu/Mo-Ti double layer etched using an etchant composition (Example 7) according to the present invention; and
FIGS. 5 and 6 are SEM images showing the surface around the Cu wiring of a Cu/Mo-Ti double layer etched using an etchant composition of Example 1 and an etchant composition of Example 7 according to the present invention, respectively.
The present invention is directed to an etchant composition for a Cu-based metal layer, which comprises, based on the total weight of the composition, A) 5.0 ~ 25 wt% of hydrogen peroxide (H2O2), B) 0.01 ~ 1.0 wt% of a F-containing compound, C) 0.1 ~ 5.0 wt% of an azole compound, D) 0.1 ~ 10.0 wt% of one or more compounds selected from among phosphonic acid derivatives and salts thereof, and E) a remainder of water.
In the present invention, the Cu-based metal layer, which contains Cu therein, may have a single layer structure or a multilayer structure including a double layer and the like, and examples thereof include a single layer of Cu or Cu alloy, and a multilayer such as a Cu-Mo layer, or a Cu-Mo alloy layer. The Cu-Mo layer includes a Mo layer and a Cu layer formed on the Mo layer, and the Cu-Mo alloy layer includes a Mo alloy layer and a Cu layer formed on the Mo alloy layer. Furthermore, the Mo alloy layer can be composed of Mo and one or more selected from among titanium (Ti), tantalum (Ta), chromium (Cr), nickel (Ni), neodymium (Nd), and indium (In).
In the etchant composition according to the present invention, the A) hydrogen peroxide (H2O2) is a main component for etching the Cu-based metal layer, and is used in an amount of 5.0 ~ 25 wt% based on the total weight of the composition. If the amount of the A) hydrogen peroxide is less than 5.0 wt%, the Cu-based metal may not be etched or the etching rate may become too slow. In contrast, if the amount thereof exceeds 25 wt%, the total etching rate may become fast, making it difficult to control the process.
In the etchant composition according to the present invention, the B) F-containing compound is a compound which dissociates in water to produce F ion. The B) F-containing compound functions to remove the inevitably generated etching residue from the etchant which etches the Cu layer and the Mo layer simultaneously. The B) F-containing compound is used in an amount of 0.01 ~ 1.0 wt% based on the total weight of the composition. If the amount of the B) F-containing compound is less than 0.01 wt%, etching residue may result. In contrast, if the amount thereof exceeds 1.0 wt%, the rate at which the glass substrate is etched may increase.
The B) F-containing compound may include any material used in the art without limitation so long as it dissociates in water to produce F ion or polyatomic F ions when in solution, and may include one or more selected from the group consisting of ammonium fluoride (NH4F), sodium fluoride (NaF), potassium fluoride (KF), ammonium bifluoride (NH4FHF), sodium bifluoride (NaFHF) and potassium bifluoride (KFHF).
In the etchant composition according to the present invention, the C) azole compound functions to adjust the rate at which the Cu-based metal is etched and to reduce CD loss of the pattern so that the process margin is increased. The C) azole compound is used in an amount of 0.1 ~ 5.0 wt% based on the total weight of the composition. If the amount of the C) azole compound is less than 0.1 wt%, the etching rate may increase and thus too much CD loss may result. In contrast, if the amount thereof exceeds 5.0 wt%, the Cu etching rate may decrease and the Mo or Mo alloy etching rate may increase, and thus the Mo or Mo alloy may be over-etched undesirably causing under-cut.
Examples of the C) azole compound include aminotetrazole, benzotriazole, tolytriazole, pyrazole, pyrrole, imidazole, 2-methylimidazole, 2-ethylimidazole, 2-propylimidazole, 2-aminoimidazole, 4-methylimidazole, 4-ethylimidazole, and 4-propylimidazole, which may be used alone or in mixtures of two or more.
In the etchant composition according to the present invention, the D) one or more compounds selected from among phosphonic acid derivates and salts thereof function to chelate Cu ions dissolved in the etchant when a Cu layer is etched, so as to suppress the activity of Cu ions to thereby inhibit the decomposition of hydrogen peroxide. When the activity of Cu ions is reduced in this way, the etching process will be stable while the etchant is being used. The D) one or more compounds selected from among phosphonic acid derivates and salts thereof are used in an amount of 0.1 ~ 10.0 wt% based on the total weight of the composition. If the amount of the D) one or more compounds selected from among phosphonic acid derivates and salts thereof is less than 0.1 wt%, etching uniformity may be lowered and decomposition of hydrogen peroxide may be accelerated. In contrast, if the amount thereof exceeds 10.0 wt%, the etching rate may becomes too fast.
In one or more compounds selected from among phosphonic acid derivates and salts thereof, a typical example of the phosphonic acid derivative may include 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP), and a typical example of the salt of phosphonic acid derivative may include a sodium or potassium salt of HEDP.
In the etchant composition according to the present invention, the E) water is not particularly limited but may include deionized water. Particularly useful is deionized water having a resistivity (which is the degree of ions being removed from water) of 18 ㏁/㎝ or more.
Also, the etchant composition according to the present invention may further comprise F) one or more compounds selected from among acetates and peracetates. These compounds play a role in increasing the uniformity of etching.
As such, one or more compounds selected from among acetates and peracetates may be used in an amount of 0.05 ~ 5.0 wt% based on the total weight of the composition. If the amount of one or more compounds selected from among acetates and peracetates is less than 0.05 wt%, etching uniformity may be lowered. In contrast, if the amount thereof exceeds 5.0 wt%, the etching rate may become too slow.
In one or more compounds selected from among acetates and peracetates, typical examples of the acetates may include ammonium acetate, sodium acetate, and potassium acetate, and typical examples of the peracetates may include ammonium peracetate, sodium peracetate, and potassium peracetate.
Moreover, the etchant composition according to the present invention may further comprise a surfactant. The surfactant functions to lower surface tension so as to increase etching uniformity. The surfactant is not particularly limited so long as it is resistant to the etchant composition according to the present invention and has compatibility, but may include one or more selected from the group consisting of an anionic surfactant, a cationic surfactant, an amphoteric surfactant, a non-ionic surfactant, and a polyhydric alcohol surfactant.
Also, the etchant composition according to the present invention may further comprise a typical additive, in addition to the above components. Examples of the additive may include a sequestering agent, an anticorrosive agent and so on.
The etchant composition comprising the A) hydrogen peroxide (H2O2), the B) F-containing compound, the C) azole compound, the D) one or more compounds selected from among phosphonic acid derivates and salts thereof, and the E) water may be prepared using typically known methods, and preferably is of a purity suitable for semiconductor processes.
The etchant composition according to the present invention may etch all of a gate electrode, gate wiring, source/drain electrodes and data wiring of a liquid crystal display made of Cu-based metal.
In addition, the present invention is directed to a method of etching a Cu-based metal layer, comprising I) forming a Cu-based metal layer on a substrate, II) selectively forming a photosensitive material layer on the Cu-based metal layer, and III) etching the Cu-based metal layer using the etchant composition according to the present invention.
In the etching method according to the present invention, the photosensitive material may be a typical photoresist, and the photosensitive material layer may be selectively formed using typical exposure and development.
In addition, the present invention is directed d to a method of fabricating an array substrate for a liquid crystal display, comprising a) forming gate wiring on a substrate, b) forming a gate insulating layer on the substrate including the gate wiring, c) forming a semiconductor layer on the gate insulating layer, d) forming source/drain electrodes on the semiconductor layer, and e) forming a pixel electrode connected to the drain electrode, wherein a) may comprise forming a Cu-based metal layer on the substrate and etching the Cu-based metal layer using the etchant composition according to the present invention, thus forming the gate wiring, and d) may comprise forming a Cu-based metal layer on the semiconductor layer and etching the Cu-based metal layer using the etchant composition according to the present invention, thus forming the source/drain electrodes.
The array substrate for a liquid crystal display may be a TFT array substrate.
A better understanding of the present invention may be obtained through the following examples which are set forth to illustrate, but are not to be construed to limit the present invention.
Examples 1 to 12: Preparation of Etchant Composition for Cu-based Metal layer
Etchant compositions of Examples 1 to 12 were prepared using the components shown in Table 1 below.
Table 1
H2O2(wt%) NH4F(wt%) Aminotetrazole(wt%) HEDP(wt%) Ammonium Acetate(wt%) Deionized Water
Ex.1 5 0.05 0.5 0.5 - Remainder
Ex.2 15 0.1 0.6 1.0 - Remainder
Ex.3 18 0.07 0.6 3.0 - Remainder
Ex.4 20 0.5 1.0 4.0 - Remainder
Ex.5 22 0.2 0.5 7.0 - Remainder
Ex.6 25 0.1 1.0 9.0 - Remainder
Ex.7 5 0.05 0.5 0.5 0.2 Remainder
Ex.8 15 0.1 0.6 1.0 0.5 Remainder
Ex.9 18 0.07 0.6 3.0 0.2 Remainder
Ex.10 20 0.5 1.0 4.0 2.0 Remainder
Ex.11 22 0.2 0.5 7.0 3.0 Remainder
Ex.12 25 0.1 1.0 9.0 4.0 Remainder
* HEDP: 1-hydroxyethylidene-1,1-diphosphonic acid
Test Example 1: Evaluation of Properties of Etchant Composition
Etching of Cu-based metal layers (Cu single layer and Cu/Mo-Ti double layer) was performed using the etchant compositions of Examples 1 to 12. Upon etching, the temperature of the etchant composition was set to about 30℃, but may appropriately vary depending on the other process conditions and factors. Furthermore, although the etching time may vary depending on the etching temperature, it was generally set to about 30 ~ 180 sec. The cross-section profile of the etched Cu-based metal layer in the etching process was observed using SEM (S-4700, available from Hitachi). The results are shown in Table 2 below.
Table 2
Etching Rate (Å/sec)
Cu Single Layer Cu/Mo-Ti Double Layer
Cu Mo
Ex.1 40 ~ 60 40 ~ 60 6 ~ 8
Ex.2 60 ~ 90 60 ~ 90 5 ~ 8
Ex.3 20 ~ 40 20 ~ 40 4 ~ 6
Ex.4 40 ~ 60 40 ~ 60 6 ~ 8
Ex.5 50 ~ 80 50 ~ 80 6 ~ 8
Ex.6 70 ~ 90 70 ~ 90 6 ~ 8
Ex.7 40 ~ 60 40 ~ 60 6 ~ 8
Ex.8 60 ~ 90 60 ~ 90 5 ~ 8
Ex.9 20 ~ 40 20 ~ 40 4 ~ 6
Ex.10 40 ~ 60 40 ~ 60 6 ~ 8
Ex.11 50 ~ 80 50 ~ 80 6 ~ 8
Ex.12 70 ~ 90 70 ~ 90 6 ~ 8
As is apparent from Table 2, evaluating the etching rates of Examples 1 to 12 shows these etching rates to be appropriate. From FIGS. 1 and 2 showing the Cu/Mo-Ti etched using the composition of Example 1 and from FIGS. 3 and 4 showing the Cu/Mo-Ti etched using the composition of Example 7, it can be seen that the Cu-based metal layer etched using the etchant composition of Example 1 or 7 represents a good etching profile. Also, from FIG. 5 showing the Cu/Mo-Ti etched using the composition of Example 1 and from FIG. 6 showing the Cu/Mo-Ti etched using the composition of Example 7, it can be seen that when the Cu-based metal layer is etched using the etchant composition of Example 1 or 7, there is no etching residue.
Therefore, the etchant composition according to the present invention is advantageous because of the superior taper profile of the Cu-based metal layer, pattern linearity, and appropriate etching rate, and in particular there is no etching residue left behind after etching.
Test Example 2: Evaluation of the Number of Processing Substrates by Etchant Composition
Changes in side etch (㎛) were measured depending on the Cu concentration using the etchant composition of Comparative Example 1 (which is a conventional etchant composition) and the etchant compositions of Examples 3 and 9 according to the present invention as shown in Table 3 below. The side etch indicates a distance between the edge of the photoresist and the edge of the lower metal, as measured after etching. In case that the side etch changes, signal transmission rates may vary upon driving a TFT, undesirably causing stains. For this reason, changes in side etch should be minimized. The present evaluation was carried out on the premise that when changes of side etch in an etching process is within ±0.1 ㎛, the continuous use of the etchant composition is possible.
Table 3
C.Ex.1 Ex.3 Ex.9
H2O2/Malonic Acid/NaH2PO4/Iminodiacetic Acid/Imidazole/NH4F H2O2/NH4F/Aminotetrazole/HEDP H2O2/NH4F/ Aminotetrazole/ HEDP/Ammonium Acetate
(25/2/1/0.5/1/0.1) wt% (18/0.07/0.6/3) wt% (18/0.07/0.6/3/0.2) wt%
The Number of Processing Sheets Cu ppm Side Etch(㎛) Side Etch(㎛) Side Etch(㎛)
0 0.68 0.69 0.69
400 0.65 0.69 0.69
1100 0.69 0.68 0.68
1900 0.69 0.68 0.68
2700 0.65 0.67 0.67
4000 0.63 0.66 0.66
4500 0.58 0.66 0.66
5000 0.55 0.66 0.66
6000 0.50 0.66 0.66
As is apparent from Table 3, whereas the conventional etchant composition of Comparative Example 1 may be used until Cu is dissolved out to 4500 ppm, the etchant compositions of Examples 3 and 9 according to the present invention may be used until Cu is dissolved out to 6000 ppm.
Compared to the etchant composition of Example 3, the etchant composition of Example 9 further comprising the acetate has no difference in the side etch for any number of processing substrates. However, the acetate functions to prevent taper rounding of the upper Cu layer which may occur in proportion to the increase in the number of processing substrates when the etchant composition such as Example 3 is used.

Claims (11)

  1. A method of fabricating an array substrate for a liquid crystal display, comprising:
    a) forming a gate wiring on a substrate;
    b) forming a gate insulating layer on the substrate including the gate wiring;
    c) forming a semiconductor layer on the gate insulating layer;
    d) forming source/drain electrodes on the semiconductor layer; and
    e) forming a pixel electrode connected to the drain electrode,
    wherein a) comprises forming a Cu-based metal layer on the substrate and etching the Cu-based metal layer using an etchant composition, thus forming the gate wiring,
    d) comprises forming a Cu-based metal layer on the semiconductor layer and etching the Cu-based metal layer using the etchant composition, thus forming the source/drain electrodes, and
    the etchant composition comprises based on total weight of the composition A) 5.0 ~ 25 wt% of hydrogen peroxide (H2O2), B) 0.01 ~ 1.0 wt% of a fluorine-containing compound, C) 0.1 ~ 5.0 wt% of an azole compound, D) 0.1 ~ 10.0 wt% of one or more compounds selected from among phosphonic acid derivatives and salts thereof, and E) a remainder of water.
  2. The method according to claim 1, wherein the array substrate for a liquid crystal display is a thin film transistor (TFT) array substrate.
  3. An etchant composition for a copper-based metal layer, comprising based on total weight of the composition:
    A) 5.0 ~ 25 wt% of hydrogen peroxide (H2O2);
    B) 0.01 ~ 1.0 wt% of a fluorine-containing compound;
    C) 0.1 ~ 5.0 wt% of an azole compound;
    D) 0.1 ~ 10.0 wt% of one or more compounds selected from among phosphonic acid derivatives and salts thereof; and
    E) a remainder of water.
  4. The etchant composition according to claim 3, further comprising 0.05 ~ 5.0 wt% of one or more compounds selected from among acetates and peracetates.
  5. The etchant composition according to claim 3, wherein the B) fluorine-containing compound comprises one or more selected from the group consisting of ammonium bifluoride (NH4FHF), potassium bifluoride (KFHF), sodium bifluoride (NaFHF), ammonium fluoride (NH4F), potassium fluoride (KF), and sodium fluoride (NaF).
  6. The etchant composition according to claim 3, wherein the C) azole compound comprises one or more selected from the group consisting of aminotetrazole, benzotriazole, tolytriazole, pyrazole, pyrrole, imidazole, 2-methylimidazole, 2-ethylimidazole, 2-propylimidazole, 2-aminoimidazole, 4-methylimidazole, 4-ethylimidazole, and 4-propylimidazole.
  7. The etchant composition according to claim 3, wherein the D) one or more compounds selected from among phosphonic acid derivatives and salts thereof comprise one or more selected from the group consisting of 1-hydroxyethylidene-1,1-diphosphonic acid, a sodium salt of 1-hydroxyethylidene-1,1-diphosphonic acid, and a potassium salt of 1-hydroxyethylidene-1,1-diphosphonic acid.
  8. The etchant composition according to claim 4, wherein the one or more compounds selected from among acetates and peracetates comprise one or more selected from the group consisting of ammonium acetate, sodium acetate, potassium acetate, ammonium peracetate, sodium peracetate, and potassium peracetate.
  9. The etchant composition according to claim 3, wherein the copper-based metal layer is a single layer of copper or copper alloy, a copper-molybdenum layer comprising a molybdenum layer and a copper layer formed on the molybdenum layer, or a copper-molybdenum alloy layer comprising a molybdenum alloy layer and a copper layer formed on the molybdenum alloy layer.
  10. A method of etching a copper-based metal layer, comprising:
    forming a copper-based metal layer on a substrate;
    selectively forming a photosensitive material layer on the copper-based metal layer; and
    etching the copper-based metal layer using the etchant composition of claim 3.
  11. An array substrate for a liquid crystal display, comprising one or more selected from among a gate wiring, and source/drain electrodes, each of which is etched using the etchant composition of claim 3.
PCT/KR2010/005484 2009-08-20 2010-08-19 Method of fabricating array substrate for liquid crystal display WO2011021860A2 (en)

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KR20140060679A (en) * 2012-11-12 2014-05-21 동우 화인켐 주식회사 Manufacturing method of an array substrate for liquid crystal display
KR20140084417A (en) * 2012-12-26 2014-07-07 동우 화인켐 주식회사 Echaing composition for preparing a channel of thin film transistor and method of preparing a channel of thin film transistor
CN110147008B (en) * 2013-07-03 2022-03-22 东友精细化工有限公司 Method for manufacturing array substrate for liquid crystal display
TWI640655B (en) * 2013-12-23 2018-11-11 韓商東友精細化工有限公司 Method of preparing array of thin film transistor and etchant composition for molybdenum-based metal film/metal oxide film
JP6657770B2 (en) 2014-11-27 2020-03-04 三菱瓦斯化学株式会社 Liquid composition and etching method using the same
JP6531612B2 (en) 2014-11-27 2019-06-19 三菱瓦斯化学株式会社 Liquid composition and etching method using the same
KR102293675B1 (en) * 2015-03-24 2021-08-25 동우 화인켐 주식회사 Etching solution composition for copper-based metal layer and method for etching copper-based metal layer using the same
JP6337922B2 (en) * 2015-08-03 2018-06-06 三菱瓦斯化学株式会社 Etching solution for etching multilayer thin film including copper layer and titanium layer, etching method using the same, and substrate obtained by using the etching method
CN106835138B (en) * 2015-12-03 2019-02-19 东友精细化工有限公司 Etchant, array substrate for display device and its manufacturing method
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CN114164003A (en) * 2021-12-06 2022-03-11 Tcl华星光电技术有限公司 Etchant composition for display panel and etching method of display panel

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